Process of using grinding glass sands



Feb.27, 1940. J. R. JONES PROCESS OF USING GRINDING GLASS SANDS Filed March" 28, 1958 PIPE FeoM Feat/Grip 72 000 To' REcsn/s lea Paar/cuss PIPE To GRAasE QWW Liz/v55 ELJ O E Patented Feb. 27, 1940 UNITED STATES PATENT OFFICE PROCESS OF USING GRINDING GLASS SANDS Application March 28,

v 2 Claims.

In the grinding and polishing of glass to form plate glass, sand (or similar substances) is frequently used as'an abrading or polishing material, the sand being fed by water to the surface of 6, the sheet of glass and rubber thereon by iron rubbers. In this operation the sand particles become broken and reduced in size. It has been the practice to pass the sludge coming from the 0 erations.

I have discovered, however, that the inferiority of the recovered sands is not ,due to this reason, but is due to the fact that the sand coming from v a grinding table contains small particles of iron 26 removed from the grinding heads in the grinding of the glass. The classification or grading of the sand has been generally efiected by subjecting a mixture of different grain size to the action of flowing water, the grading action being obtained 3CD by selecting the velocity of the waterin several settling tanks. Such a process of size grading is effective only if the particles treated are of uniform specific gravity. The iron particles due totheir high specific gravity-are deposited in the 35, several tanks along with said particles of much I greater size. My invention therefore contemplates the re moval of the ironparticlesfrom the slurry coming from the grinding machines prior to the 40 grading .Of the grains thereof.

In the accompanying drawing in which corresponding marks of reference are used to indicate corresponding parts,,Figure 1 is a diagrammatic representation of an apparatus suitable for car- 45 rying out this invention and I ilgrgure 2 is a view of suitable magnetic sepa 1938, Serial No. 198,589

A is a grinding table movable in the direction of the arrow on which is laid in the well known manner a layer of glass to be ground or polished. The movement of this table carries such glass beneath the rotating iron grinding heads C C andv C which are fed by a mixture of sand and water from the grading tanks D D and D .A suitable trough D is located beneath the grinding table for collecting the slurry resulting from the grinding operations of the several heads and this slurry is according to present practice returned to the first of the grading tanks D by means of the pump F and pipe line G. Itis not thought necessary to describe the construction of the grading tanks as these may be of any approved construction.

To avoid the deleterious efiect which has been stated to result from the presence of iron particles in the sand there is located somewhere in this line, preferably at the sump H, a magnetic separator I, a conventional showing ofwhich is found in Figure 2 and which comprises a. magnetized pulley i, the lower edge of which is immersed in the sludge and on the upper surface of which bears a rubber scraper i The pulley attracts to it in its rotationthe iron particles contained in the slurry and these are removed from the pulley by the scraper aided by water spray i if desired.

Having thus described my invention what I desire to secure by Letters Patent is:

1. The process of using glass grinding sands which involves feeding such sands to grinding heads in the presence of water, separating the iron particles contained in the slurry from the grinding tablesfrom the sand contained therein, classifying the sand according to its particle size and returning the graded sand to heads in accordance with its rain size. r

2. The hereinbefore described process which comprises removing iron particles from the slurry of glass grinding .machines, separating the sand remaining in the slurry according to particle size arh feeding theseparated sand to glass grinding heads.

JAMES Jom. 

